Radar system including balun

Abstract

A balun includes a first port connected with a port connection part, a second port connected with the port connection part at a point separated by λ 0 /4 from a connection point of the first port and the port connection part, and a third port connected with the port connection part at a point separated by λ 0 /2 from a connection point of the second port and the port connection part. A maximum width of the second port and the third port are larger than a width at a region connected with the port connection part and larger than a width at a distal end, respectively. And a maximum distance between the second port and the third port is larger than a distance between the connection points with the port connection part and larger than a distance between the distal ends.

1 . A balun comprising:
 a first port to/from which a signal having a wavelength of λ 0  is input/output, the first port being connected with a port connection part;   a second port connected with the port connection part at a point separated by λ 0 /4 from a connection point of the first port and the port connection part; and   a third port connected with the port connection part at a point separated by λ 0 /2 from a connection point of the second port and the port connection part to have an impedance matching with the second port,   wherein a maximum width of the second port is larger than a width of the second port in a region in which the second port is connected with the port connection part and larger than a width of a distal end of the second port,   a maximum width of the third port is larger than a width of the third port in a region in which the third port is connected with the port connection part and larger than a width of a distal end of the third port, and   a maximum distance between the second port and the third port which face each other is larger than a distance from the connection point of the port connection part and the second port to the connection point of the port connection part and the third port and larger than a distance from the distal end of the second port to the distal end of the third port.   
     
     
         2 . The balun as claimed in  claim 1 , wherein the port connection part and the first to third ports are formed on a single-layer substrate. 
     
     
         3 . The balun as claimed in  claim 1 , wherein the second port and the third port comprises a first sub port, a second sub port, and a third sub port, respectively,
 the second sub port is disposed between the first sub port and the third sub port, and   the second sub port of the second port and the second sub port of the third port have a bent shape such that a distance between the second sub port of the second port and the second sub port of the third port which face each other is decreased.   
     
     
         4 . The balun as claimed in  claim 3 , wherein the third sub port of the second port and the third sub port of the third port have a bent shape such that a distance between the third sub port of the second port and the third sub port of the third port which face each other is decreased. 
     
     
         5 . The balun as claimed in  claim 3 , wherein a width of the second sub port is larger than that of the first sub port and larger than that of the third sub port. 
     
     
         6 . A radar system comprising a balun, the balun comprising:
 a first port to/from which a signal having a wavelength of λ 0  is input/output, the first port being connected with a port connection part;   a second port connected with the port connection part at a point separated by λ 0 /4 from a connection point of the first port and the port connection part; and   a third port connected with the port connection part at a point separated by λ 0 /2 from a connection point of the second port and the port connection part to have an impedance matching with the second port,   wherein a maximum width of the second port is larger than a width of the second port in a region in which the second port is connected with the port connection part and larger than a width of a distal end of the second port,   a maximum width of the third port is larger than a width of the third port in a region in which the third port is connected with the port connection part and larger than a width of a distal end of the third port, and   a maximum distance between the second port and the third port which face each other is larger than a distance from the connection point of the port connection part and the second port to the connection point of the port connection part and the third port and is larger than a distance from the distal end of the second port to the distal end of the third port.